EP1566213A1 - Imprinted organic-inorganic hybrid gel comprising an organic complexing agent using pi-pi and/or pi-n interactions - Google Patents

Abstract

A sol-gel method for preparing an imprinted hybrid organic-inorganic gel (A), containing organic complexant(s) involves polycondensing a complexing functionalized metal alkoxide (I), in presence of water, an optionally functionalized metal alkoxide (II/III) and a template (IV), and washing to eliminate (IV). A sol-gel method for preparing an imprinted hybrid organic-inorganic gel (A), containing at least one organic complexant showing pi -pi or pi -n interactions with other organic molecules accepting n- or pi -electrons, involves: (1) polycondensing at least one functionalized metal alkoxide of formula L-(CH2)x-M(OR1>)n (I), in presence of (a) water, (b) a metal alkoxide of formula M(OR2>)m (II) and/or a functionalized metal alkoxide of formula (R3>)yM(OR2>)z (III), the concentration ratio of (I) to (II) and/or (III) being at most 1/5 (preferably ca. 1/50) and (c) a template (IV) comprising an organic molecule accepting n- or pi -electrons and able to form complexes with the complexing function in the group L of (I); and (2) washing the hybrid gel to eliminate the template (IV). M : silicon (Si; preferred), titanium (Ti), zirconium (Zr) or aluminum (Al) and M is the same in all of (I) - (III); or M = Si or Al in all of (I) - (III); n : 3 (if M = Si, Ti or Zr) or 2 (if M = Al); m : 4 (if M = Si, Ti or Zr) or 3 (if M = Al); y + z : 4 and z = at least 2 if M = Si, Ti or Zr; or y + z : 3 and z = at least 2 if M = Al; R1>, R2>1-12C alkyl (preferably Me and/or Et); R3>1-12C alkyl, aryl or aralkyl (preferably Me); L : organic group containing at least one organic complexing function able to form pi -pi or pi -n interactions with other organic molecules accepting n- or pi -electrons (i.e. (IV)). An independent claim is included for the hybrid gels (A) obtained by the process.

Description

The present invention relates to the manufacture of organic hybrid gels - sol-gel-printed inorganic materials and their use for separation, extraction and detection (in the form of a chemical sensor) of chemical species with electron-withdrawing groups, such as 2,4-dinitrotoluene (DNT) and 1,3-dinitrobenzene (DNB).

Various processes for extracting aromatic compounds, containing optionally heteroatoms, using a complexing agent based on an acceptor π electrons are described in WO 02/24836 and WO 02/24837. These methods the purpose of denitrogenation and desulphurisation of petroleum fractions by extraction of polyaromatic compounds such as thiophene derivatives, especially the dibenzothiophene and its derivatives, or the nitrogenous compounds of pyrrole type, indole, carbazole and their derivatives. The presence of this type of compounds in fuels is generally undesirable because they are a source of air pollution (oxides of sulfur, generators of acid rain and oxides of nitrogen or carbon, responsible for the increase in global temperature and the deterioration of the ozone layer). The materials used have a selective complexing agent for all compound rich in π or n electrons but they do not have controlled porosity. They do not are therefore not able to discriminate compounds belonging to the same family but having different steric hindrance.

The use of sol-gel materials is commonly used for the extraction of metal cations. Thus, patent FR 2,770,153 describes the use of sol-gel materials inorganic-organic hybrids synthesized according to the imprint technique molecule for the extraction of metal cations such as lanthanides and actinides. The extracting entity, which may in particular be amino, ether, hydroxy, amido, pyridino or bipyridino, is integrated in the structure of the gel during its each organic complexing molecule is covalently bound to a or several atoms of the network. However, the process used is catalyzed by the compound nucleophilic ammonium fluoride, which has repercussions on the structure of the obtained material (Boury B et al, New J. Chem 1999, 23, 531-538). In addition, only the use of the material for extraction in an aqueous medium is described.

US Pat. No. 6,057,377 describes the use of hybrid sol-gel materials, synthesized according to the molecular fingerprinting method, for selective extraction of phenylphosphonic acid used as a template molecule. The monomer complexing agent, 3-methoxypropyl-1-guanidine chloride, is covalently integrated sol-gel during its manufacture; complexation taking place through interactions of hydrogen bond type and non-type π-π and / or π-n. Acid extraction Phenylphosphonic acid is favored over that of diisopropylphenylphosphonate. Accessibility to complexing sites is managed by the porosity of the sol-gel material.

US Pat. No. 6,251,280 describes the use of mesoporous sol-gel materials coupled with the introduction into the gel of a complexing molecule made according to the molecular fingerprinting technique for the separation and detection of metals toxic and various molecules (herbicides, amino acids, drugs, explosives ...). Among these molecules the inventors claim the detection of trinitrotoluene. Molecules The complexing agents used seem to be able to interact with the target molecule only dative bonds and hydrogen bonding and not by interactions of the type π-π and / or π-n. A dative bond is a covalent bond in which the electronic doublet enters the 2 atoms is brought by one of the 2 atoms. A link of typeπ-π and / or π-n is not not a covalent bond, it corresponds to an orbital recovery. In addition, the mesoporous material is made before the introduction of the complexing molecule and not in situ. The process used is therefore complex and long. The structure of the material obtained is highly dependent on the process used.

Nitrate compounds such as 2,4-dinitrotoluene (DNT) and 1,3-dinitrobenzene (DNB) are products which can inhibit the polymerisation by radical which is a mode of polymerization commonly used in the technique of the molecular imprint.

The inventors surprisingly discovered that it was possible to manufacture a printed organic-inorganic hybrid gel having at least one complexing agent organic interaction involving π-π and / or π-n interactions with other molecules organic acceptor of n or π electrons by a sol-gel type process. The stoichiometry and the molecular structure of the solid can thus be precisely controlled. The porosity of the materials and the complexing organic group can be modified to suit the products of interest. This technique has advantages to be a method of chemical synthesis of metal oxides by soft and allow the synthesis of porosity gel defined and controlled. It also allows, during the gel manufacture, in situ incorporation of complexing organic compound.

a) la polymérisation par polycondensation, en présence d'eau, sans catalyseur, d'au moins un alcoxyde métallique fonctionnalisé de formule (I), en présence d'un alcoxyde métallique choisi parmi les alcoxydes métalliques de formule (II) ou les alcoxydes métalliques fonctionnalisés de formule (III) ou leurs mélanges : L-(CH₂)_x-M(OR¹)_n M(OR²)_m (R³)_yM(OR²)_z dans lesquelles soit M est identique dans chacune des formules I, II et III et représente Si, Ti, Zr ou Al, avantageusement Si, soit M représente Si ou Al dans chacune des
formules I, II et III,
n=3 lorsque M représente Si, Ti ou Zr ou n=2 lorsque M représente Al,
m=4 lorsque M représente Si, Ti ou Zr ou m=3 lorsque M représente Al,
y+z=4 et z est au moins égal à 2 lorsque M représente Si, Ti ou Zr ou y+z=3 et z est au moins égal à 2 lorsque M représente Al,
R¹ et R² représentent indépendamment l'un de l'autre un groupe alkyle en C₁-C₁₂, avantageusement un groupe méthyle et/ou éthyle,
R³ représente un groupe alkyle en C₁-C₁₂, un groupe aryle ou arylalkyle, avantageusement un groupe méthyle,
x= 0 à 12, de préférence, x = 3,
L représente un groupe organique comprenant au moins une fonction organique complexante pouvant former des interactions de type π-π et/ou π-n avec d'autres molécules organiques acceptrices d'électrons n ou π,
et en présence d'un gabarit constitué par une molécule organique acceptrice d'électrons n ou π et pouvant former un complexe avec la fonction organique complexante du groupe organique L,
le rapport de la concentration en composé de formule (I) / la concentration en composés de formules (II) et (III) est d'au plus 1/5, avantageusement d'environ 1/50,

b) lavage du gel hybride obtenu à l'étape a) afin de supprimer le gabarit.

The present invention relates to a process for the preparation by sol-gel of a printed organic-inorganic hybrid gel having at least one organic complexing agent involving interactions of the π-π and / or π-n type with other organic molecules. acceptors of electrons n or π, characterized in that it comprises

a) the polycondensation polymerization, in the presence of water, without catalyst, of at least one functionalized metal alkoxide of formula (I), in the presence of a metal alkoxide chosen from metal alkoxides of formula (II) or alkoxides functionalized metal of formula (III) or mixtures thereof: L- (CH ₂ ) _x -M (OR ¹ ) _n M (OR ² ) _m (R ³ ) _y M (OR ² ) _z in which either M is identical in each of formulas I, II and III and represents Si, Ti, Zr or Al, advantageously Si, or M represents Si or Al in each of
formulas I, II and III,
n = 3 when M represents Si, Ti or Zr or n = 2 when M represents Al,
m = 4 when M represents Si, Ti or Zr or m = 3 when M represents Al,
y + z = 4 and z is at least 2 when M is Si, Ti or Zr or y + z = 3 and z is at least 2 when M is Al,
R ¹ and R ² represent, independently of each other, a C ₁ -C ₁₂ alkyl group, advantageously a methyl and / or ethyl group,
R ³ represents a C ₁ -C ₁₂ alkyl group, an aryl or arylalkyl group, advantageously a methyl group,
x = 0 to 12, preferably x = 3,
L represents an organic group comprising at least one complexing organic function capable of forming π-π and / or π-n-type interactions with other n- or π-electron-accepting organic molecules,
and in the presence of a template consisting of an organic acceptor molecule of n or π electrons and capable of forming a complex with the organic complexing function of the organic group L,
the ratio of the concentration of compound of formula (I) / the concentration of compounds of formulas (II) and (III) is at most 1/5, advantageously about 1/50,

b) washing the hybrid gel obtained in step a) to remove the template.

The concentration of compound (I) in the material is always lower than that compounds (II) and (III). Indeed, the need to form a rigid cage around the ligand / template complex at the time of material formation involves a strong concentration of compounds (II) and (III) relative to the compound (I).

For the purposes of the present invention, the term "aryl group" means any aromatic C ₄ -C _{12 group} . Advantageously, it is a phenyl group.

For the purposes of the present invention, the term "arylalkyl group" means any aryl group as defined above bonded via a C ₁ -C ₆ alkyl group. Advantageously, it is a benzyl group.

Advantageously, the polymerization of step a) is carried out in the presence of a mixture of metal alkoxides of formula (II) and metal alkoxides functionalized compounds of formula (III).

Advantageously, the organic complexing function of the organic group L is a poly or monoaromatic function substituted by one or more groups electron donors π or n.

un de leur dérivé ou leur mélange.Even more advantageously, the L group is chosen from the group consisting of indole, carbazole, pyrrole, acridine, quinoline, anthracene, benzothiophene, dibenzothiophene, the group of formula

one of their derivative or their mixture.

   et

In a particular embodiment of the invention, the functionalized metal alkoxide of formula (I) is chosen from the group consisting of

and

Advantageously, R ³ represents a methyl, ethyl, octyl, benzyl or phenyl group. Advantageously, it is a methyl group.

In an advantageous embodiment, the template is chosen from the group consisting of aromatic molecules containing electron-withdrawing groups directly attached to the nucleus, advantageously groups of the -COOH type, halo, cyano, etc.

Advantageously, the template is chosen from the group constituted by the acid picric acid, haloaromatic compounds such as, for example, dichlorobenzene and tetrachlorobenzene, dicyanobenzene, tetracyanobenzene, DNT or DNB. Advantageously, it is DNT or DNB.

In an advantageous embodiment of the invention, the washing step b) is made with a suitable solvent, i.e. able to break the interactions involved during complexing and solubilizing the template immobilized in the material. In a way Advantageously, it is toluene or acetonitrile. This washing step allows, besides remove the template, remove the unreacted monomers. advantageously this step takes place after the step of ripening, drying and grinding of the gel.

Advantageously, the group of formula II is TMOS tetramethoxysilane. Of Advantageously, the group of formula III is methyltrimethoxysilane MeTMOS. Advantageously, the groups of formula II and III are chosen from the group consisting of with phenyltriethoxysilane, phenyltrimethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, octyltrimethoxysilane, methyloctyldimethoxysilane, propyltrimethoxysilane or mixtures thereof.

To implement the process for preparing the hybrid gel of the invention, generally dissolves the metal alkoxides in a suitable solvent. Advantageously, it is an organic solvent miscible with water, so advantageous chosen from the group consisting of tetrahydrofuran and an alcohol, advantageously ethanol. Then we add water to start the phenomenon of condensation.

The amounts of solvent are generally such that they correspond to 0.5 to 1 ml of solvent per mmol of metal and the amount of water added must correspond to at least 0.5 equivalents of water per alkoxy group OR ¹ and optionally OR ² and OR ³ present in the metal alkoxides used.

The reaction can be carried out at ambient temperature, with stirring, in then allowing the reaction medium to rest until gelation (for a period of maturing, advantageously of the order of a few hours to several days, so even more advantageous of the order of 3 to 4 days) and then allowing aging for example a week.

In an advantageous embodiment, the metal alkoxide of formula (II) or (III) or their mixture is solubilized in a suitable solvent, advantageously ethanol, and then distilled water is added. After mixing, the metal alkoxide functionalized formula (I) is introduced. The template is then added to the solution. The Clear solution is stirred and poured into a plastic tube. The pH of this solution is advantageously weakly acidic or neutral, even more advantageously in the range 4.5-5. The mixture is stored hermetically at 25.degree. period of ripening, advantageously of the order of a few hours to several days, even more advantageously of the order of 3 to 4 days. The gel formed is then allowed to air dry at room temperature for 3-4 weeks. It is then ground and then washed with a suitable solvent, advantageously acetonitrile. This wash eliminates the template but also unreacted monomers. The The material is then dried under vacuum for 12 hours.

The present invention also relates to an organic-inorganic hybrid gel printed, having at least one organic complexing agent involving interactions of type π-π and / or π-n with other organic molecules accepting n or π electrons, obtainable by the process according to the present invention.

The inorganic-organic hybrid gel comprises an inorganic pattern network in which the organic complexing agents L which can extract the products are integrated interest, each organic molecule being covalently attached to one or more atoms of the network. In the gel of the invention, the inorganic units may be silica gel type, titanium oxide gel, zirconium oxide gel or alumina gel.

The present invention further relates to the use of the organic-inorganic hybrid gel printed according to the present invention for separation, extraction or detection of chemical species comprising electron-accepting groups n or π, advantageously chosen from the group consisting of DNT or DNB.

In an advantageous embodiment, the chemical species to be extracted, to separate or detect are selected from the group consisting of aromatic molecules having electron-withdrawing groups directly attached to the nucleus, advantageously groups of the type -COOH, halo, cyano, etc.

Advantageously, the chemical species to be extracted, separated or detected are selected from the group consisting of picric acid, haloaromatic compounds such as, for example, dichlorobenzene and tetrachlorobenzene, dicyanobenzene, tetracyanobenzene, DNT or DNB. Advantageously, it is DNT or DNB.

Currently the limit of detection of the chemical species according to the present invention is due to the chromatography apparatus which is used to detect the presence of DNT in solution after extraction. Typically concentrations of from 1x10 ^-6 mol.L ^-1 can be detected which means that the material may advantageously extract solutions having concentrations ranging from 1x10 ^-3 mol L ^-1 to 1x10 ^-6 mol L ^{- 1} .

DNT or DNB are byproducts of 2,4,6-trinitrotoluene synthesis (TNT) which is the most used explosive. A significant amount of its products (several% by weight) remain mixed with TNT. 2,4-dinitrotoluene and 1,3-dinitrobenzene have a much higher vapor pressure than TNT and are stable in the environment which allows their detection in the atmosphere.

• le 2,6-di-t-butyltoluène (DitBuT),
• le décane (C₁₀),
• le nitrobenzène (NBz),
• le 4-nitrobiphényl (4NBiPh),
• le 4-nitro-bromobenzyl (4NBzBr),
• le 5-méthyl-2-nitroanisole (5M2A),
• le 1,3-dinitrobenzène (DNB).

Advantageously, it is a selective extraction of DNT with respect to interfering 2,4-dinitrotoluene (DNT). These interferents are as follows:

• 2,6-di- t- butyltoluene (DitBuT),
• decane (C ₁₀ ),
• nitrobenzene (NBz),
• 4-nitrobiphenyl (4NBiPh),
• 4-nitro-bromobenzyl (4NBzBr),
• 5-methyl-2-nitroanisole (5M2A),
• 1,3-dinitrobenzene (DNB).

Advantageously, it is an extraction in liquid or gaseous phase.

Advantageously, the hybrid organic-inorganic gel printed according to the present The invention is used in a liquid phase extraction process by contacting of the solution containing the compound to be extracted with the gel, followed by the separation of the gel having fixed the compound to be extracted.

When using a gel in granular form, the extraction process corresponds to an extraction chromatography and it can be implemented in a column filled with granular gel.

In the case where the gel is in the form of a thin layer, it can be realized extraction by a membrane separation technique by putting into circulation a side of the membrane the aqueous solution containing the molecules to extract and the other side of the membrane, an aqueous reextraction solution. Extraction is also possible in the gas phase because the complexation is mainly based on steric effects (however pi-pi and pi-n interactions also exist).

Advantageously, the extracted chemical species is released for its characterization. This release can be achieved by various means (heating and use of a neutral gas to help desorption of the gel such as nitrogen or helium).

The examples which follow, given by way of non-limiting indication, illustrate the synthesis of hybrid gels according to the invention and their use for the extraction, complexing and detection of chemical species comprising electron-withdrawing groups.
For the synthesis of the functionalized alkoxysilanes, all the manipulations are carried out under an argon atmosphere. The solvents are anhydrous and the reactants are commercial.

Example 1 Synthesis of the monomer 1 (N-3-trifluoromethylphenyl-N ' not -propyl-3-triéthoxysilylurée)

Analyse IR (KBr; cm^-1): 3350 (NH); 3100 (CH_aro); 2980 (CH₃); 2930 (CH₂); 2885 (CH₂); 1656 (C=O); 1560 (CNH); 1342 (CN); 1260 (CF); 1170 (CF); 1080 (SiO); 957 (CH_aro); 875 (CH_aro); 790 (CF)In a tricolor of 50 mL, 15 mL of tetrahydrofuran and 1 g (4-10 ^-4 mol) of isocyanatopropyl triethoxysilane are introduced. Then 651 mg (4-10 ^-4 moles) of trifluoromethylaniline are added dropwise to the reaction medium. The solution is then stirred and heated to reflux. The disappearance of trifluoromethylamine is monitored by thin layer chromatography (TLC): silica gel, CH ₂ Cl ₂ ). Once all the trifluoromethylamine has been consumed, the solvent is removed under vacuum. A white solid is obtained (quantitative yield).

IR (KBr, cm ^-1 ): 3350 (NH); 3100 (CH _aro ); 2980 (CH ₃ ); 2930 (CH ₂ ); 2885 (CH ₂ ); 1656 (C = O); 1560 (CNH); 1342 (CN); 1260 (CF); 1170 (CF); 1080 (SiO); 957 (CH _aro ); 875 (CH _aro ); 790 (CF)

The following examples illustrate the development of hybrid silica gels according to the invention. The materials are synthesized by hydrolysis and polycondensation of alkoxysilanes such as tetramethoxysilane (TMOS), methyltrimethoxysilane (MeTMOS) and compound 1 (N-3-trifluoromethylphenyl-N ' n -propyl-3-triethoxysilylurea), in the presence of water and ethanol (without catalyst). At first, the TMOS is solubilized in ethanol and then distilled water is added. After mixing, compound 1 is introduced. DNT is added to the solution. MeTMOS can also be optionally added. The clear solution is stirred and poured into a plastic tube. The mixture is stored hermetically at 25 ° C for a ripening period of 3 to 4 days. The gel formed is then left to air dry at room temperature for 3-4 weeks. It is then milled and then washed with acetonitrile using a soxhlet to remove DNT. The material is then dried under vacuum for 12 hours.
Compound 1 must not be the only organic-inorganic monomer used in the context of the sol-gel process so that the material that it is desired to obtain preserves its complexing properties. Thus, in the examples which follow, the TMOS and / or the MeTMOS always accompany the compound 1.

Example 2 Preparation of Hybrid Silica Gel Printed 2a

1,52 g de TMOS (10 x 10^-3 mol)

735 mg d'eau

1,88 g d'éthanol

38 mg de DNT (2,1 x 10^-4 mol)

87 mg de produit 1 (2,1 x 10^-4 mol)

On obtient une poudre blanche
Analyse IR (KBr, cm^-1) : 3430 (NH + OH); 1652 (C=O); 1565 (CNH); 1342 (CN); 1087 (SiO); 950 (CH_aro); 800 (CH_aro)The reagents used are as follows:

1.52 g of TMOS (10 x 10 ^-3 mol)

735 mg of water

1.88 g of ethanol

38 mg of DNT (2.1 x 10 ^-4 mol)

87 mg of product 1 (2.1 x 10 ^-4 mol)

We obtain a white powder
IR (KBr, cm ^-1 ): 3430 (NH + OH); 1652 (C = O); 1565 (CNH); 1342 (CN); 1087 (SiO); 950 (CH _aro ); 800 (CH _aro )

Example 3 Preparation of Hybrid Silica Gel Printed 2b

1,37 g de TMOS (9 x 10^-3 mol)

138 mg de MeTMOS (1 x 10^-3 mol)

735 mg d'eau

1,88 g d'éthanol

38 mg de DNT (2,1 x 10^-4 mol)

87 mg de produit 1 (2,1 x 10^-4 mol)

On obtient une poudre blanche
Analyse IR (KBr, cm^-1) : 3430 (NH + OH); 1651 (C=O); 1564 (CNH); 1341 (CN); 1087 (SiO); 949 (CH_aro); 800 (CH_aro)The reagents used are as follows:

1.37 g of TMOS (9 x 10 ^-3 mol)

138 mg of MeTMOS (1 x 10 ^-3 mol)

735 mg of water

1.88 g of ethanol

38 mg of DNT (2.1 x 10 ^-4 mol)

87 mg of product 1 (2.1 x 10 ^-4 mol)

We obtain a white powder
IR (KBr, cm ^-1 ): 3430 (NH + OH); 1651 (C = O); 1564 (CNH); 1341 (CN); 1087 (SiO); 949 (CH _aro ); 800 (CH _aro )

Example 4 Preparation of Hybrid Silica Gel Printed 2c

1,37 g de TMOS (5 x 10^-3 mol)

138 mg de MeTMOS (5 x 10^-3 mol)

735 mg d'eau

1,88 g d'éthanol

38 mg de DNT (2,1 x 10^-4 mol)

87 mg de produit 1 (2,1 x 10^-4 mol)

On obtient une poudre blanche
Analyse : IR (KBr, cm^-1) : 3430 (NH + OH); 1650 (C=O); 1564 (CNH); 1342 (CN); 1087 (SiO); 950 (CH_aro); 800 (CH_aro)The reagents used are as follows:

1.37 g of TMOS (5 x 10 ^-3 mol)

138 mg of MeTMOS (5 x 10 ^-3 mol)

735 mg of water

1.88 g of ethanol

38 mg of DNT (2.1 x 10 ^-4 mol)

87 mg of product 1 (2.1 x 10 ^-4 mol)

We obtain a white powder
Analysis: IR (KBr, cm ^-1 ): 3430 (NH + OH); 1650 (C = O); 1564 (CNH); 1342 (CN); 1087 (SiO); 950 (CH _aro ); 800 (CH _aro )

Example 5 Preparation of Hybrid Silica Gel Printed 2d

1,36 g de TMOS (10 x 10^-3 mol)

735 mg d'eau

1,88 g d'éthanol

38 mg de DNT (2,1 x 10^-4 mol)

87 mg de produit 1 (2,1 x 10^-4 mol)

On obtient une poudre blanche
Analyse IR (KBr, cm^-1) : 3430 (NH + OH); 1651 (C=O); 1565 (CNH); 1342 (CN); 1089 (SiO); 949 (CH_aro); 800 (CH_aro)The reagents used are as follows:

1.36 g of TMOS (10 x 10 ^-3 mol)

735 mg of water

1.88 g of ethanol

38 mg of DNT (2.1 x 10 ^-4 mol)

87 mg of product 1 (2.1 x 10 ^-4 mol)

We obtain a white powder
IR (KBr, cm ^-1 ): 3430 (NH + OH); 1651 (C = O); 1565 (CNH); 1342 (CN); 1089 (SiO); 949 (CH _aro ); 800 (CH _aro )

Example 6 Competitive Extraction Test with Printed Hybrid Gels (2a, 2b, 2c, 2d)

The tests in competitive extraction are carried out according to the following experimental protocol:
20 mg of printed hybrid materials (2a, 2b, 2c, 2d) are introduced into a glass pill container and then 1 ml of heptane solution containing DNT and an interfering agent is added. The concentration of each product in the solution is equal to 1x10 ^-4 mol.L ^-1 . The pillbox is then shaken on a vibrating table until reaching the thermodynamic equilibrium of the system. Then, the solutions before competitive extraction and after competitive extraction (respectively C _i and C _f ) are analyzed by gas chromatography.

Analytical conditions:

• Varian CPSil5-CB wide boron column (length 15m, inner diameter 0.53mm, film thickness 3 μm),
• Injector temperature 260 ° C
• FID detector temperature 260 ° C
• oven 80 ° C to 200 ° C maintained 5min with a slope of 10 ° C / min.

• le 2,6-di-t-butyltoluène (DitBuT),
• le décane (C₁₀),
• le nitrobenzène (NBz),
• le 4-nitrobiphényl (4NBiPh),
• le 4-nitro-bromobenzyl (4NBzBr),
• le 5-méthyl-2-nitroanisole (5M2A),
• le 1,3-dinitrobenzène (DNB).

Leurs formules développées sont rassemblées dans le tableau 1 ci-après.

The 2,4-dinitrotoluene (DNT) interferants used in competitive extraction are as follows:

• 2,6-di- t- butyltoluene (DitBuT),
• decane (C ₁₀ ),
• nitrobenzene (NBz),
• 4-nitrobiphenyl (4NBiPh),
• 4-nitro-bromobenzyl (4NBzBr),
• 5-methyl-2-nitroanisole (5M2A),
• 1,3-dinitrobenzene (DNB).

Their developed formulas are collated in Table 1 below.

The materials are evaluated according to their ability to extract the TSD from each interferent. The percentages of extraction, calculated from C _i and C _f (concentrations measured by gas chromatography of each product before and after extraction, example below for a product A), are determined by the following equation: E AT (%) = VS AT i - VS AT f VS AT i × 100

Il apparaít clairement que le gel selon la présente invention est sélectif des composés DNB et DNT. Toutefois le composé 5M2A est aussi extrait en proportion similaire (légère sélectivité envers le DNT et le DNB) en raison de la présence du groupement éther qui peut interagir avec les groupements silanols résiduels du gel ou avec la fonction urée du monomère.The results of competitive extraction tests with DNT-printed sol-gel materials (2a, 2b) are summarized in Tables 2 to 8 below:

It is clear that the gel according to the present invention is selective of DNB and DNT compounds. However, the 5M2A compound is also extracted in a similar proportion (slight selectivity towards the DNT and the DNB) because of the presence of the ether group which can interact with the residual silanol groups of the gel or with the urea function of the monomer.

Claims (10)

Process for the sol-gel preparation of a printed organic-inorganic hybrid gel having at least one organic complexing agent involving π-π and / or π-n-type interactions with other electron accepting organic molecules or π, characterized in that it comprises a) the polycondensation polymerization, in the presence of water, of at least one functionalized metal alkoxide of formula (I), in the presence of a metal alkoxide chosen from metal alkoxides of formula (II) or functionalized metal alkoxides of formula (III) or mixtures thereof: L- (CH ₂ ) _x- M (OR ¹ ) _n M (OR ² ) _m (R ³ ) _y M (OR ² ) _z wherein either M is the same in each of formulas I, II and III and is Si, Ti, Zr or Al, preferably Si, or M is Si or Al in each of Formulas I, II and III,
n = 3 when M represents Si, Ti or Zr or n = 2 when M represents Al,
m = 4 when M represents Si, Ti or Zr or m = 3 when M represents Al,
y + z = 4 and z is at least 2 when M is Si, Ti or Zr or y + z = 3 and z is at least 2 when M is Al,
R ¹ and R ² represent, independently of each other, a C ₁ -C ₁₂ alkyl group, advantageously a methyl and / or ethyl group,
R ³ represents a C ₁ -C ₁₂ alkyl group, an aryl or arylalkyl group, advantageously a methyl group,
x = 0 to 12, preferably x = 3,
L represents an organic group comprising at least one complexing organic function capable of forming π-π and / or π-n-type interactions with other n- or π-electron-accepting organic molecules,
and in the presence of a template consisting of an organic acceptor molecule of n or π electrons and capable of forming a complex with the organic complexing function of the organic group L,
the ratio of the concentration of compound of formula (I) / the concentration of compounds of formulas (II) and (III) is at most 1/5, advantageously about 1/50, b) washing the hybrid gel obtained in step a) to remove the template. Process according to Claim 1, characterized in that the organic complexing function of the organic group L is a poly or monoaromatic function substituted by one or more electron donor groups. Process according to Claim 2, characterized in that the L group is chosen from the group consisting of indole, carbazole, pyrrole, acridine, quinoline, anthracene, benzothiophene, dibenzothiophene and the group of formula

or their mixture. Process according to Claim 3, characterized in that the functionalized metal alkoxide of formula (I) is chosen from the group consisting of

and

Method according to any one of the preceding claims, characterized in that the template is chosen from the group consisting of the DNT or the DNB. Process according to any one of the preceding claims, characterized in that the group of formula II is the TMOS and the group of formula III is MeTMOS. Printed organic-inorganic hybrid gel having at least one complexing agent organic interaction involving π-π and / or π-n interactions with other molecules organic acceptors of n or π electrons, obtainable by the process according to any of claims 1 to 6. Use of the organic-inorganic hybrid gel printed according to the claim 7 for the separation, extraction or detection of chemical species with electron-accepting groups n or π, advantageously chosen from the group constituted by the DNT or the DNB. Use according to Claim 8, characterized in that it is an extraction in the liquid or gaseous phase. Use according to Claim 9, characterized in that the extracted chemical species is released for characterization.